About half of the city of Sacramento proper does [1], not that you need meters to restrict lawn watering or car washing.

[1] http://portal.cityofsacramento.org/Utilities/Conservation/Wa...

While some restrictions can be enforced via other means, metering and noting aberrantly high consumption patterns can both show unobserved violations and find other causes of wasting -- e.g., broken mains or pipes on a property.